Estimation device, estimation method, and diagnosis method

Abstract

To provide an estimation device for estimating the whole discharge characteristics of a power storage element, a diagnosis device for diagnosing the capacitance of the power storage element on the basis of the whole discharge characteristics, a method for estimation, and a method for diagnosis.SOLUTION: The estimation device includes: an acquisition unit for acquiring time-series data of the current and the voltage of a power storage element; an electric amount calculation unit for calculating the time-series data of an electric amount on the basis of the acquired time-series data of the current; a generation unit for generating a partial charge-discharge profile of the power storage element on the basis of the acquired time-series data of the voltage and the time-series data of the electric amount; and an estimation unit for estimating the whole charge characteristics of the power storage element on the basis of the partial charge-discharge profile.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an estimation device , Push and a determination method and a diagnosis method therefor.

Background Art

[0002] Energy storage devices are widely used in uninterruptible power supply devices, DC or AC power supply devices included in stabilized power supplies, etc. In addition, the use of energy storage devices in large-scale power systems for storing power generated by renewable energy or existing power generation systems is expanding.

[0003] It is known that energy storage devices deteriorate as they repeat charging and discharging, and their full charge capacity gradually decreases. Patent Document 1 discloses a full charge and discharge method technique for measuring the capacity of an energy storage device by removing some of the energy storage devices from an energy storage system in which the energy storage devices are mounted, charging the removed energy storage devices to a fully charged state, and then fully discharging the energy storage devices with a constant discharge current.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When adopting the full charge and discharge method, it is necessary to stop the operation of the energy storage system. It is also conceivable to use a limited part (a part of the operation pattern) that can diagnose the capacity of the energy storage device from the operation data (operation pattern) of the energy storage system without stopping the operation of the energy storage system. However, with this method, only partial discharge characteristics can be obtained, so it is difficult to improve the accuracy of capacity diagnosis.

[0006] The present invention relates to an estimation device for estimating the overall discharge characteristics of an energy storage device, Push An object of the present invention is to provide an estimation method and a diagnosis method.

Means for Solving the Problems

[0007] An estimation device according to an aspect of the present invention includes an acquisition unit that acquires time-series data of current and voltage of a power storage element, an electric quantity calculation unit that calculates time-series data of an electric quantity based on the time-series data of current acquired by the acquisition unit, a generation unit that generates a partial charge / discharge profile of the power storage element based on the time-series data of voltage acquired by the acquisition unit and the time-series data of electric quantity calculated by the electric quantity calculation unit, and an estimation unit that estimates the overall discharge characteristics of the power storage element based on the partial charge / discharge profile.

Advantages of the Invention

[0008] According to the above aspect, it is possible to estimate the overall discharge characteristics of the power storage element at a predetermined time point after the start of operation without stopping the operation of the power storage system.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] The estimation device includes an acquisition unit that acquires time-series data of the current and voltage of a power storage element, an electric quantity calculation unit that calculates time-series data of the electric quantity based on the time-series data of the current acquired by the acquisition unit, a generation unit that generates a partial charge / discharge profile of the power storage element based on the time-series data of the voltage acquired by the acquisition unit and the time-series data of the electric quantity calculated by the electric quantity calculation unit, and an estimation unit that estimates the overall discharge characteristics of the power storage element based on the partial charge / discharge profile.

[0011] The estimation method includes acquiring time-series data of the current and voltage of a power storage element, calculating time-series data of the electric quantity based on the acquired time-series data of the current, generating a partial charge / discharge profile of the power storage element based on the acquired time-series data of the voltage and the calculated time-series data of the electric quantity, and estimating the overall discharge characteristics of the power storage element based on the partial charge / discharge profile.

[0012] The acquisition unit of the estimation device acquires time-series data of the current and voltage of a power storage element. The time-series data of the current and voltage are data during charging or discharging of the power storage element. The charging current or discharging current does not have to be constant. Also, the SOC (State of Charge) region and voltage region during charging, and the SOC region and voltage region during discharging may be limited. The acquisition unit acquires time-series data of the power storage element in an actual operation pattern (not in a state of operation stop or not in a specific operation pattern for capacity diagnosis). The time-series data may be real-time data or historical data of a past predetermined period.

[0013] The electric quantity calculation unit calculates time-series data of the electric quantity based on the acquired time-series data of the current. The electric quantity can be obtained by integrating the current. For example, the electric quantity Q(t) can be calculated by the formula {Q(t)=ΣI(t)·Δt}.

[0014] The generation unit generates a partial charge / discharge profile of the energy storage element based on the acquired time-series data of the voltage and the calculated time-series data of the electrical quantity. For example, the partial charge / discharge profile can be drawn by plotting the time-series data on a two-dimensional coordinate system with the electrical quantity on the horizontal axis and the voltage on the vertical axis. The partial charge / discharge profile uses the word "partial" to distinguish it from the overall discharge characteristics, and it is a partial charge / discharge profile between the upper limit voltage and the lower limit voltage set for the energy storage element, or a partial charge / discharge profile between the upper limit SOC and the lower limit SOC set for the energy storage element.

[0015] The estimation unit estimates the overall discharge characteristics of the energy storage element based on the partial charge / discharge profile. The estimation unit may estimate the overall discharge characteristics of the energy storage element based on the positive electrode single-pole characteristics, the negative electrode single-pole characteristics, and the partial charge / discharge profile of the energy storage element. The positive electrode single-pole characteristics are the characteristics indicated by the positive electrode discharge curve. The positive electrode discharge curve may be a plot of the electrical quantity and the potential corresponding to the electrical quantity with the electrical quantity on the horizontal axis and the potential on the vertical axis. The negative electrode single-pole characteristics are the characteristics indicated by the negative electrode discharge curve. The negative electrode discharge curve may be a plot of the electrical quantity and the potential corresponding to the electrical quantity with the electrical quantity on the horizontal axis and the potential on the vertical axis. The difference between the potential of the positive electrode and the potential of the negative electrode is the voltage of the energy storage element. The overall discharge characteristics are, for example, the characteristics indicated by a continuous discharge curve between the upper limit voltage and the lower limit voltage set for the energy storage element, or the characteristics indicated by a continuous discharge curve between the upper limit SOC and the lower limit SOC set for the energy storage element.

[0016] The estimation unit adjusts at least one of the positive electrode single-pole characteristics and the negative electrode single-pole characteristics so that the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics of the energy storage element approaches (approximates) the partial charge / discharge profile. The overall discharge characteristics can be estimated from the difference between the adjusted positive electrode single-pole characteristics and the negative electrode single-pole characteristics.

[0017] With the above configuration, it is possible to estimate the overall discharge characteristics of the energy storage element based on the time-series data of the current and voltage obtained in the actual operation pattern without stopping the operation of the energy storage system or operating the energy storage system in a specific operation pattern for capacity diagnosis.

[0018] The estimation device may include a correction unit that corrects the positive electrode single-pole characteristics and / or the negative electrode single-pole characteristics so that the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics approaches the partial charge-discharge profile. The correction unit may be a part of the estimation unit.

[0019] The correction unit corrects, for example, the effectiveness (utilization rate) of the positive electrode. The correction of the effectiveness corresponds to correcting an index indicating the available amount of the active material in the positive electrode. The correction unit corrects the capacity at the discharge start position of the positive electrode single-pole characteristics. Specifically, the capacity at the discharge start position can be corrected by translating the discharge curve of the positive electrode parallel to the axis indicating the capacity. The correction of the discharge start position corresponds to correcting an index indicating the oxidative decomposition of the electrolyte.

[0020] The correction unit corrects the capacity at the discharge start position of the negative electrode single-pole characteristics. Specifically, it can be corrected by translating the negative electrode discharge curve parallel to the axis indicating the capacity. The correction of the discharge start position corresponds to correcting an index indicating the growth of the SEI (Solid Electrolyte Interphase) film.

[0021] With the above configuration, it becomes possible to bring the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics closer to the partial charge-discharge profile.

[0022] The estimation device may include a complementation unit that complements the overall discharge characteristics of the energy storage element obtained partially.

[0023] The complementation unit can complement the part of the overall discharge characteristics other than the partial charge-discharge profile. The complementation unit may be a part of the estimation unit.

[0024] The estimation unit can estimate the overall discharge characteristics by connecting the discharge characteristics corresponding to the partial charge-discharge profile and the complementary discharge characteristics.

[0025] The estimation device includes a plot generation unit that generates an electric quantity-voltage plot of the energy storage element over a required period based on the time-series data of the voltage acquired by the acquisition unit and the time-series data of the electric quantity calculated by the electric quantity calculation unit, and a representative value calculation unit that calculates a representative electric quantity and a representative voltage representing the electric quantity and voltage in each divided region obtained by dividing the electric quantity-voltage plot generated by the plot generation unit with a predetermined electric quantity width. The generation unit may generate a partial charge-discharge profile of the required period based on the representative electric quantity and representative voltage for each divided region calculated by the representative value calculation unit.

[0026] The plot generation unit may generate an electric quantity-voltage plot of the energy storage element over a required period. For example, an electric quantity-voltage plot can be drawn by plotting the time-series data of the electric quantity and voltage on a two-dimensional coordinate with the electric quantity on the horizontal axis and the voltage on the vertical axis. As the required period, an appropriate period such as one day, one week, one month, three months, or six months can be used. For example, it may be set with reference to a period in which the operation pattern of the energy storage element does not vary significantly, a period in which the error in calculating the electric quantity when integrating the current does not exceed the allowable range, and the like.

[0027] The electric quantity-voltage plot generated by the plot generation unit is divided into divided regions with a predetermined electric quantity width. For example, the electric quantity-voltage plot drawn on a two-dimensional coordinate with the electric quantity on the horizontal axis and the voltage on the vertical axis is divided into divided regions by dividing the electric quantity with a predetermined electric quantity width. The divided region is a vertically long rectangular region where the horizontal direction is the predetermined electric quantity width and the vertical direction is the voltage. In each divided region, a part of the electric quantity-voltage plot is plotted.

[0028] The representative value calculation unit may calculate a representative electrical quantity and a representative voltage that represent the electrical quantity and the voltage for each divided region from the electrical quantity-voltage plots in each divided region. The representative electrical quantity and the representative voltage may be calculated, for example, as follows.

[0029] In the first method, the average value of the voltages represented by the electrical quantity-voltage plots within the divided region may be used as the representative voltage, and the center of the electrical quantity width of the divided region may be used as the representative electrical quantity. In the second method, the voltage with respect to the current within the divided region may be plotted, and the voltage value at which the current value of the approximate curve (for example, an approximate straight line) of the plot is 0 may be used as the representative voltage, and the center of the electrical quantity width of the divided region may be used as the representative electrical quantity.

[0030] The generation unit may generate a partial charge / discharge profile for a required period based on the representative electrical quantity and the representative voltage for each divided region. The partial charge / discharge profile can be drawn by plotting the representative electrical quantity and the representative voltage for each divided region in a two-dimensional coordinate system with the electrical quantity on the horizontal axis and the voltage on the vertical axis.

[0031] With the above configuration, a partial charge / discharge profile for a required period (for example, a period during which the operation pattern of the energy storage element does not differ significantly, a period during which the calculation error of the electrical quantity does not exceed the allowable range, etc.) can be generated.

[0032] The generation unit of the estimation device may generate a partial charge / discharge profile for a continuous period in which the plurality of required periods are continuous based on the partial charge / discharge profiles for each of the plurality of consecutive required periods.

[0033] The generation unit may generate partial charge-discharge profiles for each of a plurality of consecutive required periods, and generate a partial charge-discharge profile for a continuous period in which the plurality of required periods are consecutive, based on each of the generated partial charge-discharge profiles. For example, let the plurality of consecutive required periods be a first period and a second period. In each of the first period and the second period, the operation pattern of the energy storage element does not differ significantly, or the error in calculating the amount of electricity when integrating the current does not exceed the allowable range. However, in the overall period combining the first period and the second period, it is assumed that the operation pattern of the energy storage element may differ significantly, or the error in calculating the amount of electricity may exceed the allowable range. In such a case, by using the partial charge-discharge profiles generated in each of the first period and the second period to generate a partial charge-discharge profile for a continuous period in which the first period and the second period are consecutive, it is possible to accurately generate the partial charge-discharge profile without being affected by changes in the operation pattern of the energy storage element or errors in calculating the amount of electricity.

[0034] The estimation device includes a profile correction unit that corrects at least one of the first partial charge-discharge profile and the second partial charge-discharge profile by moving it along the axis of the amount of electricity on the partial charge-discharge profile so that the first partial charge-discharge profile of one period and the second partial charge-discharge profile of the other period among consecutive required periods approach each other. The generation unit may generate a partial charge-discharge profile for the continuous period based on the correction by the profile correction unit.

[0035] The profile correction unit can make the first partial charge-discharge profile and the second partial charge-discharge profile approach each other on the partial charge-discharge profile by correcting at least one of the first partial charge-discharge profile and the second partial charge-discharge profile by moving it along the axis of the amount of electricity on the partial charge-discharge profile. Thereby, even if the respective partial charge-discharge profiles are shifted due to, for example, an error in calculating the amount of electricity, between one period and the other period of consecutive required periods, the shift can be reduced, and a partial charge-discharge profile for a connection period longer than the required period can be generated.

[0036] The diagnostic device includes a diagnostic unit that diagnoses the full charge capacity of the energy storage element based on the overall discharge characteristics estimated by the aforementioned estimation device.

[0037] The diagnostic method includes obtaining time-series data of the current and voltage of the energy storage element, calculating time-series data of the electrical quantity based on the obtained time-series data of the current, generating a partial charge / discharge profile of the energy storage element based on the obtained time-series data of the voltage and the calculated time-series data of the electrical quantity, estimating the overall discharge characteristics of the energy storage element based on the positive electrode single-pole characteristics, negative electrode single-pole characteristics, and the partial charge / discharge profile of the energy storage element, and diagnosing the full charge capacity of the energy storage element based on the estimated overall discharge characteristics.

[0038] The diagnostic unit of the diagnostic device diagnoses the full charge capacity of the energy storage element based on the overall discharge characteristics estimated by the estimation device. The full charge capacity (diagnostic capacity) of the energy storage element can be calculated by subtracting the electrical quantity corresponding to the upper limit voltage from the electrical quantity corresponding to the lower limit voltage of the overall discharge characteristics.

[0039] With the above configuration, it is possible to diagnose the full charge capacity of the energy storage element from the actual operation pattern without stopping the operation of the energy storage system or operating it in a specific operation pattern for capacity diagnosis.

[0040] The diagnostic device may further include a statistical value calculation unit that calculates a statistical value of the full charge capacity over a plurality of periods using the full charge capacity of the energy storage element diagnosed by the diagnostic unit for each period, a determination unit that determines the validity / invalidity of the full charge capacity for each period diagnosed by the diagnostic unit using the statistical value calculated by the statistical value calculation unit, and a capacity calculation unit that calculates the full charge capacity of the energy storage element over a required period by excluding the full charge capacity determined to be invalid by the determination unit.

[0041] The statistical value calculation unit calculates statistical values of the full charge capacity over a plurality of periods using the full charge capacity of the energy storage element diagnosed by the diagnosis unit for each period. For example, the diagnosis unit diagnoses the full charge capacity in period A (e.g., one day, etc.), and calculates statistical values of the full charge capacity in period B over a plurality of periods A. For example, periods A1, A2, A3, A4, and A5 can be grouped together as period B. The statistical values may be, for example, the moving average R of the full charge capacity and the standard deviation σ. If the full charge capacities diagnosed in each of periods A1 to A5 are Q1 to Q5, the moving average R can be obtained by R = (Q1 + Q2 + Q3 + Q4 + Q5) / 5. The standard deviation σ can be obtained by σ = √{Σ(Qi - R) 2 / 5}.

[0042] The determination unit determines the validity / invalidity of the full charge capacity for each period diagnosed by the diagnosis unit using the calculated statistical values. The determination of validity / invalidity is, for example, to determine that it is valid if the diagnosed full charge capacity is within the range of the average R ± σ, and to determine that it is invalid if it is outside the range.

[0043] The capacity calculation unit calculates the full charge capacity of the energy storage element over a required period excluding the full charge capacity determined to be invalid. The required period C is longer than period B.

[0044] With the above configuration, even when the usage state of the energy storage element (e.g., the time ratios of charging, discharging, and rest, the SOC usage range, etc.) is different for each period, or there is a bias, highly accurate capacity diagnosis can be performed.

[0045] Hereinafter, embodiments of the estimation device, diagnosis device, estimation method, and diagnosis method will be described with reference to the drawings.

[0046] <First Embodiment> FIG. 1 is a diagram showing the configurations of the estimation device 50 and the diagnostic device 70. The estimation device 50 and the diagnostic device 70 are connected to the communication network 1. The estimation device 50 and the diagnostic device 70 may be integrated into either one of the estimation device 50 or the diagnostic device 70. A remote monitoring system 100 is connected to the communication network 1. The number of remote monitoring systems 100 may be 1 or 3 or more. The estimation device 50 and the diagnostic device 70 or one of them may be integrated into any one of the remote monitoring systems 100. The description of the estimation device 50 and the diagnostic device 70 will be given later.

[0047] FIG. 2 is a diagram showing the configuration of the remote monitoring system 100. The remote monitoring system 100 includes a communication device 10, a server device 20 connected to the communication device 10 via a communication network 2, a domain management device 30, and a power storage unit (domain) 40. The power storage unit 40 may include a plurality of banks 41. The power storage unit 40 is, for example, housed in a battery panel and used for a thermal power generation system, a megasolar power generation system, a wind power generation system, an uninterruptible power supply (UPS), a stabilized power supply system for railways, and the like. The part of the power storage unit 40 excluding the power conditioner (not shown) may also be referred to as a battery system.

[0048] An operator conducts business of designing, introducing, operating, and maintaining a power storage system including the communication device 10, the domain management device 30, and the power storage unit 40, and can remotely monitor the power storage system using the remote monitoring system 100.

[0049] The communication device 10 includes a control unit 11, a storage unit 12, a first communication unit 13, and a second communication unit 14. The control unit 11 is composed of a CPU (Central Processing Unit) or the like, and controls the entire communication device 10 using memories such as a built-in ROM (Read Only Memory) and RAM (Random Access Memory).

[0050] The storage unit 12 can use, for example, a non-volatile memory such as a flash memory. The storage unit 12 can store required information, and can store, for example, information obtained by the processing of the control unit 11.

[0051] The first communication unit 13 can communicate with the domain management device 30 (or the battery management device 44 shown in FIG. 3).

[0052] The second communication unit 14 can communicate with the server device 20 via the communication network 2.

[0053] The domain management device 30 transmits and receives information to and from each bank 41 using a predetermined communication interface.

[0054] The storage unit 12 can store the operation data acquired via the domain management device 30.

[0055] The server device 20 can collect the operation data of the power storage system from the communication device 10. The operation data includes time-series data such as current data, voltage data, and temperature data of each power storage element in the power storage system. The operation data may include data of SOC (state of charge) that can be calculated from the time-series data. The server device 20 stores the collected operation data separately for each power storage element. The server device 20 can transmit the operation data to the estimation device 50 via the communication networks 2 and 1. Note that the communication networks 1 and 2 may be a single communication network.

[0056] FIG. 3 is a diagram showing the configuration of the bank 41. The bank 41 is formed by connecting a plurality of power storage modules in series, and includes a battery management unit (BMU) 44, a plurality of power storage modules 42, and a measurement board (CMU: Cell Management Unit) 43 provided for each power storage module 42.

[0057] The power storage module 42 has a plurality of power storage cells connected in series. In this specification, the "power storage element" may mean a power storage cell, the power storage module 42, the bank 41, or a domain in which the banks 41 are connected in parallel. In the present embodiment, the measurement substrate 43 acquires power storage element information regarding the state of each power storage cell of the power storage module 42. The power storage element information includes, for example, the voltage, current, temperature, SOC (state of charge), SOH, etc. of the power storage cell. The power storage element information can be repeatedly acquired at an appropriate cycle such as 0.1 seconds, 0.5 seconds, 1 second, etc. The data in which the power storage element information is accumulated becomes part of the operation data. The "power storage element" is preferably a rechargeable one such as a secondary battery like a lead-acid battery and a lithium-ion battery, or a capacitor. A part of the power storage element may be a non-rechargeable primary battery.

[0058] The battery management device 44 can communicate with the measurement substrate 43 with a communication function by serial communication and can acquire the power storage element information detected by the measurement substrate 43. The battery management device 44 can transmit and receive information to and from the domain management device 30. The domain management device 30 aggregates the power storage element information from the battery management devices 44 of the banks belonging to the domain. The domain management device 30 outputs the aggregated power storage element information to the communication device 10. In this way, the communication device 10 can acquire the operation data of the power storage unit 40 via the domain management device 30.

[0059] As shown in FIG. 1, the estimation device 50 includes a control unit 51 that controls the entire device, a communication unit 52, a storage unit 53, an electrical quantity calculation unit 54, a generation unit 55, an estimation unit 56, a correction unit 57, and a complement unit 58. The control unit 51 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The storage unit 53 is composed of a hard disk, a semiconductor memory, etc. and stores required data.

[0060] The communication unit 52 includes a communication module and has a communication function with the diagnostic device 70 and the remote monitoring system 100 (server device 20). The communication unit 52 functions as an acquisition unit and acquires time-series data of the current and voltage of the energy storage element in the remote monitoring system 100. The time-series data of the current and voltage are data during charging or discharging of the energy storage element. For example, the charging current or discharging current does not have to be constant. The SOC (State of Charge) region and voltage region during charging, and the SOC region and voltage region during discharging may be limited. Here, "limited" means not including the entire region from the upper limit value to the lower limit value of the voltage or SOC. The communication unit 52 acquires time-series data of the energy storage element in the actual operating state (not in the state of operation stop or not in a specific operating state for capacity diagnosis). The time-series data may be real-time data or past history data.

[0061] FIG. 4 is a diagram showing an example of current data, and FIG. 5 is a diagram showing an example of voltage data. In FIG. 4, the vertical axis represents current, the positive side represents charging, and the negative side represents discharging. The horizontal axis represents time. The estimation device 50 acquires time-series current data as shown in FIG. 4. In FIG. 5, the vertical axis represents voltage, and the horizontal axis represents time. The estimation device 50 acquires time-series voltage data as shown in FIG. 5.

[0062] The storage unit 53 shown in FIG. 1 stores the time-series data acquired via the communication unit 52.

[0063] The electricity quantity calculation unit 54 calculates time-series data of the electricity quantity based on the time-series data of the current acquired via the communication unit 52. The electricity quantity can be obtained by integrating the current. For example, the electricity quantity Q(t) can be calculated by the formula {Q(t)=ΣI(t)·Δt}.

[0064] The generation unit 55 generates a partial charge / discharge profile of the energy storage element based on the time-series data of the voltage acquired via the communication unit 52 and the time-series data of the electricity quantity calculated by the electricity quantity calculation unit 54.

[0065] FIG. 6 is a diagram showing an example of a partial charge / discharge profile (a state in which plots obtained every predetermined period are overlapped). In FIG. 6, the horizontal axis represents the amount of electricity (Ah), and the vertical axis represents the voltage (V). A partial charge / discharge profile can be drawn by plotting the amount of electricity calculated by the electricity amount calculation unit 54 and the voltage at the time when the amount of electricity was obtained (the voltage corresponding to the amount of electricity).

[0066] The estimation unit 56 shown in FIG. 1 estimates the overall discharge characteristics of the energy storage element based on the positive electrode single-pole characteristics, the negative electrode single-pole characteristics, and the partial charge / discharge profile (see FIG. 6) generated by the generation unit 55. The overall discharge characteristics may be, for example, characteristics represented by a continuous discharge curve between the upper limit voltage and the lower limit voltage set for the energy storage element, or characteristics represented by a continuous discharge curve between the upper limit SOC and the lower limit SOC set for the energy storage element, but are not limited thereto.

[0067] The correction unit 57 may correct the positive electrode single-pole characteristics so that the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics approaches the partial charge / discharge profile generated by the generation unit 55. The estimation unit 56 may estimate the overall discharge characteristics of the energy storage element using the corrected positive electrode single-pole characteristics.

[0068] The correction unit 57 may correct the negative electrode single-pole characteristics so that the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics approaches the partial charge / discharge profile generated by the generation unit 55. The estimation unit 56 may estimate the overall discharge characteristics of the energy storage element using the corrected negative electrode single-pole characteristics. Hereinafter, the positive electrode single-pole characteristics and the negative electrode single-pole characteristics will be described.

[0069] FIG. 7 is a diagram showing an example of correction of the positive electrode monopole characteristics by the first parameter. The positive electrode monopole characteristics are characteristics shown by the discharge curve of the positive electrode (for example, counter electrode lithium). The discharge curve of the positive electrode is obtained by plotting the discharge charge amount (Ah) on the horizontal axis and the potential (V) on the vertical axis, and plotting the discharge charge amount and the potential corresponding to the charge amount. The first parameter is the positive electrode effectiveness (also referred to as "utilization factor"). The positive electrode effectiveness is an index indicating the available amount of the active material in the positive electrode. In FIG. 7, three positive electrode discharge curves P1, P2, and P3 are shown. The positive electrode discharge curves P1, P2, and P3 correspond to positive electrode effectivenesses of 1, 0.9, and 0.8, respectively. When the positive electrode effectiveness is 1, the energy storage element is the same as a new one, and the positive electrode effectiveness decreases as the deterioration progresses. As shown in FIG. 7, the positive electrode monopole characteristics are corrected so that the positive electrode discharge curve is scaled in the horizontal axis direction according to the positive electrode effectiveness (first parameter).

[0070] FIG. 8 is a diagram showing an example of correction of the positive electrode monopole characteristics by the second parameter. The second parameter is the discharge start position of the positive electrode. The discharge start position of the positive electrode is an index indicating the oxidative decomposition of the electrolytic solution. In FIG. 8, three positive electrode discharge curves P1, P4, and P5 are shown. The positive electrode discharge curves P1, P4, and P5 correspond to the relative positions of the start of discharge (shift to the negative side from 0 Ah) of 0 Ah, -5 Ah, and -10 Ah, respectively. As shown in FIG. 8, the positive electrode monopole characteristics are corrected so that the positive electrode discharge curve is translated in the horizontal axis direction according to the change in the relative position of the start of discharge.

[0071] FIG. 9 is a diagram showing an example of correcting the negative electrode single-pole characteristics using a third parameter. The negative electrode single-pole characteristics are characteristics indicated by the discharge curve of the negative electrode (for example, counter electrode lithium). The discharge curve of the negative electrode is obtained by plotting the discharge charge amount (Ah) on the horizontal axis and the potential (V) on the vertical axis, and plotting the discharge charge amount and the potential corresponding to the charge amount. The difference between the potential of the positive electrode and the potential of the negative electrode is the voltage of the energy storage element. The third parameter is the discharge start position of the negative electrode. The discharge start position of the negative electrode is an index indicating the growth of the SEI (Solid Electrolyte Interphase) film. In FIG. 9, three negative electrode discharge curves N1, N2, and N3 are shown. The negative electrode discharge curves N1, N2, and N3 correspond to relative positions of the start of discharge (shift to the negative side from 0 Ah) of 0 Ah, -5 Ah, and -10 Ah, respectively. As shown in FIG. 9, the negative electrode single-pole characteristics are corrected so that the negative electrode discharge curve is translated in the horizontal axis direction according to the change in the relative position of the start of discharge.

[0072] The positive electrode single-pole characteristics, the negative electrode single-pole characteristics, and the first to third parameters may be stored in the storage unit 53.

[0073] Using the above configuration, it is possible to make the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics closer to the partial charge-discharge profile.

[0074] The correction unit 57 corrects at least one of the positive electrode single-pole characteristics and the negative electrode single-pole characteristics so that the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics of the energy storage element approaches the partial charge-discharge profile generated by the generation unit 55. The estimation unit 56 can estimate the overall discharge characteristics from the difference between the corrected positive electrode single-pole characteristics and the negative electrode single-pole characteristics.

[0075] With the above configuration, without stopping the operation of the energy storage system or charging and discharging the energy storage system in a specific operation pattern for capacity diagnosis, the overall discharge characteristics of the energy storage element can be estimated based on the time-series data of the current and voltage obtained in the actual operation state. Hereinafter, the method for estimating the overall discharge characteristics will be specifically described.

[0076] FIG. 10 is a diagram showing a method for estimating a portion corresponding to a partial charge-discharge profile among overall discharge characteristics. In FIG. 10, the horizontal axis represents the amount of electricity (Ah), and the vertical axis represents voltage / potential (V). In FIG. 10A, a partial charge-discharge profile S, a positive electrode discharge curve Px, and a negative electrode discharge curve Nx are shown. By adjusting the aforementioned first parameter and second parameter, the shape of the positive electrode discharge curve Px can be adjusted to correct the positive electrode single-pole characteristics. Also, by adjusting the third parameter, the shape of the negative electrode discharge curve Nx can be adjusted to correct the negative electrode single-pole characteristics.

[0077] By adjusting at least one of the first to third parameters, at least one of the positive electrode discharge curve Px and the negative electrode discharge curve Nx is adjusted so that the difference between the potential corresponding to a certain amount of electricity of the positive electrode discharge curve Px and the potential corresponding to the same amount of electricity of the negative electrode discharge curve Nx approaches the potential corresponding to the same amount of electricity of the partial charge-discharge profile S. The difference between the potential corresponding to a certain amount of electricity of the positive electrode discharge curve Px and the potential corresponding to the same amount of electricity of the negative electrode discharge curve Nx is the voltage corresponding to the same amount of electricity of the overall discharge curve (specifically, the portion Qa corresponding to the partial charge-discharge profile S).

[0078] For example, as shown enlarged in FIG. 10B, the sum of the squares (ΣΔVi 2 ) of the voltage differences ΔVi between the voltage corresponding to a certain amount of electricity of the partial charge-discharge profile S and the voltage corresponding to the same amount of electricity of the portion Qa corresponding to the partial charge-discharge profile S in the overall discharge curve is minimized to obtain the first to third parameters. Here, the sum of the squares may handle the voltages corresponding to all amounts of electricity on the partial charge-discharge profile S.

[0079] FIG. 11 is a diagram showing a method of estimating the overall discharge characteristics by complementing parts other than the partial charge / discharge profile. The complementing part 58 complements the overall discharge characteristics of the energy storage element from the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics for capacitance bands other than the capacitance band corresponding to the partial charge / discharge profile. As described above, by adjusting at least one of the positive electrode discharge curve Px and the negative electrode discharge curve Nx so that the difference between the positive electrode discharge curve Px and the negative electrode discharge curve Nx approaches the partial charge / discharge profile S, the discharge curve Qa can be estimated for the capacitance band corresponding to the partial charge / discharge profile S. For capacitance bands other than the capacitance band corresponding to the partial charge / discharge profile S, the discharge curve Qb is complemented from the difference between the adjusted positive electrode discharge curve Px and the negative electrode discharge curve Nx. By connecting the discharge curve Qa and the discharge curve Qb, the overall discharge curve can be estimated.

[0080] FIG. 12 is a diagram showing the overall discharge curves before and after deterioration. FIG. 12A shows an example of the overall discharge curve Q of the initial energy storage element estimated by the estimation device 50, and FIG. 12B shows an example of the overall discharge curve Q' of the deteriorated energy storage element estimated by the estimation device 50. In FIG. 12A, the overall discharge curve Q is estimated based on the uncorrected (unadjusted) positive electrode discharge curve Px and negative electrode discharge curve Nx. By changing at least one of the first to third parameters in consideration of the deterioration of the energy storage element with respect to the positive electrode discharge curve Px and the negative electrode discharge curve Nx, as shown in FIG. 12B, the deteriorated positive electrode discharge curve Px' and negative electrode discharge curve Nx' can be obtained. Based on the positive electrode discharge curve Px' and the negative electrode discharge curve Nx', the overall discharge curve Q' after deterioration is estimated.

[0081] As described above, by appropriately adjusting the first to third parameters, the overall discharge characteristics conforming to the partial charge / discharge profile can be estimated.

[0082] Next, the diagnostic device 70 will be described. As shown in FIG. 1, the diagnostic device 70 includes a control unit 71 that controls the entire device, a communication unit 72, a storage unit 73, a diagnostic unit 74, a statistical value calculation unit 75, a determination unit 76, and a capacity calculation unit 77. The control unit 71 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The storage unit 73 is composed of a hard disk, a semiconductor memory, or the like, and stores required data.

[0083] The communication unit 72 acquires data regarding the overall discharge characteristics of the power storage element estimated by the estimation device 50.

[0084] The diagnostic unit 74 diagnoses the capacity of the power storage element based on the overall discharge characteristics estimated by the estimation device 50.

[0085] FIG. 13 is a diagram showing a first example of a method for diagnosing the full charge capacity of a power storage element. In FIG. 13, the horizontal axis represents the capacity (Ah), and the vertical axis represents the voltage (V). The overall discharge characteristics (reproduced overall discharge curve) estimated by the estimation device 50 reproduce the discharge curve continuously from the upper limit voltage to the lower limit voltage set for the power storage element. The full charge capacity (diagnostic capacity) of the power storage element can be calculated by subtracting the capacity corresponding to the upper limit voltage from the capacity (electric quantity) corresponding to the lower limit voltage of the overall discharge curve.

[0086] With the above configuration, even when the power storage element is operating in an actual operation pattern without stopping its operation (or without operating in a specific operation pattern for capacity diagnosis), the full charge capacity of the power storage element can be diagnosed.

[0087] The usage state of the energy storage element varies according to the period (e.g., daily, time zone, etc.). Specifically, the time ratios of charging, discharging, and rest, and the range of SOC (SOC range) in which the energy storage element is used may differ. For example, when only the charging time ratio is extremely large, the voltage of the discharge characteristics of the energy storage element becomes higher. If there are days with extremely biased usage states during a relatively long period (e.g., one week, one month, etc.), the accuracy of the capacity diagnosis value may decrease. Hereinafter, a method for solving this problem will be described.

[0088] FIG. 14 is a diagram showing a second example of a method for diagnosing the full charge capacity of an energy storage element. This method is based on the premise that the full charge capacity of the energy storage element does not change significantly over about one week or one month. In FIG. 14, period A, period B, and period C will be described as examples. Period A is, for example, a period corresponding to one day, but it may also be a time zone or the like instead of one day. Period B is composed of a plurality of period As, and period B > period A. In the example of FIG. 14, five period As are grouped together as period B. A plurality of period Bs are set by shifting period B in units of period A. Period C is a period longer than period B. In the example of FIG. 14, period C is composed of seven period As, but it may also be composed of a number of period As other than seven.

[0089] The statistical value calculation unit 75 calculates the statistical value of the full charge capacity over a plurality of periods using the full charge capacity of the energy storage element diagnosed by the diagnosis unit for each period. For example, the diagnosis unit 74 diagnoses the full charge capacity of period A and calculates the statistical value of the full charge capacity of period B over a plurality of period As. The statistical value may be, for example, the moving average R of the full charge capacity and the standard deviation σ. If the full charge capacities diagnosed in each of the five period As are Q1 to Q5, the moving average R can be obtained by R = (Q1 + Q2 + Q3 + Q4 + Q5) / 5. The standard deviation σ can be obtained by σ = √{Σ(Qi - R) 2 / 5}.

[0090] The determination unit 76 determines the validity of the full charge capacity for each period A diagnosed by the diagnosis unit 74 using the statistical value calculated by the statistical value calculation unit 75. For the determination of validity, for example, if the diagnosed full charge capacity is within the range of average R ± σ, it is determined as valid, and if it is outside the range, it is determined as invalid.

[0091] The capacity calculation unit 77 calculates the full charge capacity of the energy storage element over the required period C excluding the full charge capacity determined to be invalid by the determination unit 76.

[0092] FIG. 15 is a diagram showing the result of diagnostic capacity. As shown in FIG. 15, the true value capacity (true value of the full charge capacity) is 50.4 (Ah). When the outlier (the full charge capacity determined to be invalid) is excluded, the diagnostic capacity is 50.6 (Ah), whereas the diagnostic capacity including the outlier (diagnostic value of the full charge capacity) was 47.3 (Ah).

[0093] As described above, even when the usage state of the energy storage element (for example, the time ratio of charging, discharging, and rest, the SOC usage range, etc.) is different for each period, or there is a bias, high-precision capacity diagnosis can be performed.

[0094] FIG. 16 is a flowchart showing the processing procedure of the estimation device 50. Hereinafter, for convenience, the main body of the processing will be described as the control unit 51. The control unit 51 acquires the time-series data of the current and voltage of the energy storage element (S11) and generates a partial charge / discharge profile (S12). The control unit 51 corrects the positive electrode single-pole characteristic (S13) so that the difference between the positive electrode single-pole characteristic and the negative electrode single-pole characteristic approaches the partial charge / discharge profile, and corrects the negative electrode single-pole characteristic (S14) so that the difference between the positive electrode single-pole characteristic and the negative electrode single-pole characteristic approaches the partial charge / discharge profile.

[0095] The control unit 51 determines whether the difference between the difference between the positive electrode single-pole characteristic and the negative electrode single-pole characteristic and the partial charge / discharge profile is within the allowable range (S15). If the difference is not within the allowable range (NO in S15), the control unit 51 continues the processing from step S13. If the difference is within the allowable range (YES in S15), the control unit 51 estimates the discharge characteristic corresponding to the partial charge / discharge profile (S16).

[0096] The control unit 51 complements the discharge characteristics other than the discharge characteristics corresponding to the partial charge / discharge profile based on the difference between the corrected positive electrode single-electrode characteristics and the negative electrode single-electrode characteristics (S17), estimates the overall discharge characteristics of the storage element based on the discharge characteristics corresponding to the partial charge / discharge profile and the complemented discharge characteristics (S18), and terminates the processing.

[0097] 17 is a flowchart showing the processing procedure of the diagnostic device 70. For convenience, the following description will be given with the control unit 71 acting as the main actor in the processing. The control unit 71 diagnoses the full charge capacity of the storage element based on the estimated overall discharge characteristics (S31). The control unit 71 diagnoses the full charge capacity in each period A (S32), and calculates the average value (moving average) and standard deviation of the full charge capacity for each period B (>period A) (S33).

[0098] The control unit 71 determines whether the full charge capacity diagnosed in the period A is within a predetermined range (S34). The predetermined range can be determined by a moving average and a standard deviation. If the full charge capacity diagnosed in the period A is within the predetermined range (YES in S34), the control unit 71 determines that the full charge capacity diagnosed in the period A is a valid value (S35), and performs the process of step S37 described later.

[0099] If the full charge capacity diagnosed in period A is not within a predetermined range (NO in S34), the control unit 71 determines that the full charge capacity diagnosed in period A is an outlier (invalid) (S36), and performs averaging processing for period C using only valid full charge capacity values (S37). The control unit 71 sets the averaged full charge capacity value as the full charge capacity in period A (S38), and ends the processing.

[0100] The estimation device 50 and the diagnosis device 70 may be integrated into one device. For example, the electrical quantity calculation unit 54, the generation unit 55, the estimation unit 56, the correction unit 57, and the complementation unit 58 of the estimation device 50 may be incorporated into the diagnosis device 70.

[0101] As described above, according to the present embodiment, it is possible to provide a technique for diagnosing the full charge capacity without operating the energy storage element or operating it in a specific operation pattern for capacity diagnosis. Further, it can also be applied to the energy storage element after deterioration. Further, even when there is a bias in the usage state of the energy storage element for each period, it is possible to provide a highly accurate capacity diagnosis result.

[0102] <Second Embodiment> The operation pattern (way of use) of the energy storage element may vary depending on the period (for example, 1 day, 1 week, 1 month, 3 months, 6 months, etc.). When diagnosing the full charge capacity of the energy storage element, if the operation pattern is different within the diagnosis period, the diagnosis accuracy may decrease. In the second embodiment, a method for generating a partial charge-discharge profile will be described so that the full charge capacity can be accurately diagnosed even when the operation pattern of the energy storage element varies depending on the period. In the second embodiment, the generation unit 55 has the functions of a plot generation unit, a representative value calculation unit, and a profile correction unit.

[0103] FIG. 18 is a diagram showing an example of an electric quantity-voltage plot (Ah-V plot). In FIG. 18, the horizontal axis represents the electric quantity (Ah), and the vertical axis represents the voltage (V). The generation unit 55 may generate an electric quantity-voltage plot PL of the energy storage element over a required period (period Ai in FIG. 18) based on the time-series data of the voltage acquired via the communication unit 52 and the time-series data of the electric quantity calculated by the electric quantity calculation unit 54. The electric quantity-voltage plot (Ah-V plot) PL can be drawn, for example, by plotting the time-series data of the electric quantity and the voltage in a two-dimensional coordinate system with the horizontal axis as the electric quantity and the vertical axis as the voltage. As the required period, an appropriate period such as 1 day, 1 week, 1 month, 3 months, 6 months, etc. can be used. For example, it may be set with reference to a period in which the operation pattern of the energy storage element does not vary significantly, a period in which the error in calculating the electric quantity when integrating the current does not exceed the allowable range, and the like.

[0104] FIG. 19 is a diagram showing an example of a divided region. The generation unit 55 divides the generated (Ah-V plot) PL into divided regions divided by a predetermined amount-of-electricity width. As shown in FIG. 19, the (Ah-V plot) PL drawn on a two-dimensional coordinate with the horizontal axis being the amount of electricity (Ah) and the vertical axis being the voltage (V) is divided into divided regions divided by a predetermined amount-of-electricity width (ΔPL in FIG. 19). The divided region is a vertically long rectangular region where the horizontal direction is a predetermined amount-of-electricity width ΔPL and the vertical direction is the voltage (V). In each divided region, a part of the (Ah-V plot) PL is plotted. In FIG. 19, in the divided region ΔPL, the (Ah-V plots) PL1 and PL2 are plotted.

[0105] FIG. 20 is a diagram showing a first example of a method for calculating the representative amount of electricity and the representative voltage of a divided region. The generation unit 55 may calculate a representative amount of electricity and a representative voltage representing the amount of electricity and the voltage for each divided region from the (Ah-V plot) in each divided region. The representative amount of electricity and the representative voltage may be, for example, the average value of the voltages represented by the (Ah-V plot) in the divided region as the representative voltage and the center of the amount-of-electricity width of the divided region as the representative amount of electricity.

[0106] As shown in FIG. 20, when the voltages of the (Ah-V plots) PL1 and PL2 in the divided region are Vi (i = 1 to n), the representative voltage V (bar) may be obtained as the average of the voltages Vi. When the amounts of electricity at both ends of the divided region are Qn and Q(n + 1), the representative amount of electricity Q (bar) may be the value at the center of the amount-of-electricity width {Q(n + 1) - Qn}.

[0107] FIG. 21 is a diagram showing an example of a partial charge / discharge profile during a required period. The generation unit 55 may generate a partial charge / discharge profile during the required period based on the representative amount of electricity Q (bar) and the representative voltage V (bar) for each divided region. As shown in FIG. 21, by plotting the representative amount of electricity and the representative voltage (indicated by the symbol X in FIG. 21) for each divided region on a two-dimensional coordinate with the horizontal axis being the amount of electricity and the vertical axis being the voltage, a partial charge / discharge profile (Ah-OCV characteristic) can be drawn.

[0108] With the above configuration, it is possible to generate a partial charge / discharge profile during a required period (for example, a period in which the operation pattern of the power storage element does not vary significantly, a period in which the calculation error of the amount of electricity does not exceed the allowable range, etc.).

[0109] The method for calculating the representative voltage V (bar) is not limited to the example shown in FIG. 20.

[0110] FIG. 22 is a diagram showing a second example of a method for calculating the representative amount of electricity and the representative voltage of a divided region. As shown in FIG. 22, the voltage V with respect to the current I of (Ah-V plot) PL1 and PL2 within the divided region of the divided region is plotted on a two-dimensional coordinate of voltage and current. The voltage value (i.e., the intercept b) at the current value of 0 of the curve (a straight line V = a×I + b in FIG. 22) approximating the plot may be used as the representative voltage V (bar). The representative amount of electricity Q (bar) may be the value at the center of the electricity amount width {Q(n + 1) - Qn}, where Qn and Q(n + 1) are the amounts of electricity at both ends of the divided region.

[0111] Next, the generation of a partial charge / discharge profile during a continuous period (the entire period over a plurality of required periods) over a plurality of consecutive required periods will be described.

[0112] The generation unit 55 may generate partial charge-discharge profiles for each of a plurality of consecutive required periods, and generate a partial charge-discharge profile for a continuous period in which the plurality of required periods are consecutive, based on each of the generated partial charge-discharge profiles. For example, let the plurality of consecutive required periods be a first period and a second period. In each of the first period and the second period, the operation pattern of the power storage element does not differ significantly, or the error in calculating the amount of electricity when integrating the current does not exceed the allowable range. However, in the overall period combining the first period and the second period, there may be a significant difference in the operation pattern of the power storage element, or the error in calculating the amount of electricity may exceed the allowable range. In such a case, by using the partial charge-discharge profiles generated in each of the first period and the second period to generate a partial charge-discharge profile for the continuous period in which the first period and the second period are consecutive, it is possible to accurately generate the partial charge-discharge profile without being affected by changes in the operation pattern of the power storage element or errors in calculating the amount of electricity.

[0113] FIG. 23 is a diagram showing an example of generating a partial charge-discharge profile in a continuous period over a plurality of consecutive required periods. FIG. 23A shows the (Ah-OCV characteristic) (partial charge-discharge profile) in period A1 and the (Ah-OCV characteristic) in period A2 consecutive to period A1. The (Ah-OCV characteristic) in period A1 and the (Ah-OCV characteristic) in period A2 are different (shifted on the two-dimensional coordinate of the amount of electricity and voltage) due to various factors (for example, changes in the operation pattern of the power storage element, errors in calculating the amount of electricity, etc.).

[0114] The generation unit 55 can make the (Ah-OCV characteristic) in period A1 and the (Ah-OCV characteristic) in period A2 approach each other by moving and correcting at least one of the (Ah-OCV characteristic) (first partial charge-discharge profile) in period A1 and the (Ah-OCV characteristic) (second partial charge-discharge profile) in period A2 along the amount-of-electricity axis on the two-dimensional coordinate of the amount of electricity and voltage. FIG. 23B shows that the (Ah-OCV characteristic) in period A2 is translated parallel to the amount-of-electricity axis to make the (Ah-OCV characteristic) in period A2 approach the (Ah-OCV characteristic) in period A1.

[0115] As shown in FIG. 23C, the voltage V of the (Ah-OCV characteristic) in period A1 i,A and the voltage V of the (Ah-OCV characteristic) in period A2 i,B are minimized for the residual d therebetween. As a result, as shown in FIG. 23D, the (Ah-OCV characteristic) in period A1 and the (Ah-OCV characteristic) in period A2 may be combined to obtain a partial charge / discharge profile S for period (A1 + A2). Thus, even if the partial charge / discharge profiles are shifted due to, for example, an error in the calculation of the charge amount between one period and the other period of a continuous required period, the shift can be reduced, and a partial charge / discharge profile for a connection period longer than the required period can be generated. In the example of FIG. 23, two consecutive periods are described, but a partial charge / discharge profile can be generated in the same manner even when three or more required periods are consecutive.

[0116] The partial charge / discharge profile generated according to the second embodiment can estimate the overall charge / discharge characteristics of the power storage element by performing the same processing as in the first embodiment. Similarly, the fully charged capacity of the power storage element can be diagnosed based on the estimated overall discharge characteristics.

[0117] FIG. 24 is a flowchart showing the generation processing procedure of the partial charge / discharge profile according to the second embodiment. The control unit 51 acquires the time-series data of the current and voltage of the power storage element in period Ai (S41), integrates the acquired time-series data of the current to convert it into time-series data of the charge amount, and generates a plot of the voltage against the charge amount (Ah-V plot) (S42). The (Ah-V plot) is the one illustrated in FIG. 18.

[0118] The control unit 51 subdivides the (Ah-V plot) into divided regions with a predetermined charge amount width (S43). The subdivision of the (Ah-V plot) is the one illustrated in FIG. 19. The control unit 51 calculates the charge amount and OCV within the subdivided divided regions (S44). Here, as illustrated in FIG. 20 or FIG. 22, the representative charge amount and representative voltage for each divided region are calculated.

[0119] The control unit 51 estimates the (Ah-OCV characteristic) in the period Ai based on the representative electrical quantity and the representative voltage for each divided region (S45). The (Ah-OCV characteristic) in the period Ai is the one illustrated in FIG. 21. The control unit 51 determines the presence or absence of other periods consecutive to the period Ai (S46). If there are other periods (YES in S46), it adds 1 to i (S47) and continues the processing after step S41.

[0120] If there are no other periods (NO in S46), the control unit 51 combines the (Ah-OCV characteristics) of each of the consecutive periods Ai obtained so far in step S45 to generate a partial charge / discharge profile for the continuous period (S48) and ends the processing. The processing in step S48 is performed according to the procedure illustrated in FIG. 23.

[0121] As described above, according to the second embodiment, even when the usage of the power storage element differs for each period, the difference in the (Ah-OCV characteristic) of the power storage element for each period is corrected to generate a partial charge / discharge profile in a continuous period over a plurality of periods, and the diagnostic accuracy of the full charge capacity of the power storage element can be improved.

[0122] The embodiments are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

Explanation of Reference Numerals

[0123] 1, 2 Communication network 10 Communication device 11 Control unit 12 Storage unit 13 First communication unit 14 Second communication unit 20 Server device 30 Domain management device 40 Power storage unit 41 Bank 42 Power storage module 43 Measurement board 44 Battery management device 50 Estimation device 51 Control unit 52 Communication unit 53 Memory unit 54 Electric quantity calculation unit 55 Generation unit 56 Estimation unit 57 Correction unit 58 Completion unit 70 Diagnosis device 71 Control unit 72 Communication unit 73 Memory unit 74 Diagnosis unit 75 Statistical value calculation unit 76 Judgment unit 77 Capacity calculation unit

Claims

1. An acquisition unit that acquires time-series data of the current and voltage of an energy storage element; An electric quantity calculation unit that calculates time-series data of the electric quantity based on the time-series data of the current acquired by the acquisition unit; A generation unit that generates a partial charge / discharge profile by plotting the current integration, which is the integration of the current and time of the energy storage element, and the voltage corresponding to the current integration, based on the time-series data of the voltage acquired by the acquisition unit and the time-series data of the electric quantity calculated by the electric quantity calculation unit; An estimation unit that estimates the overall discharge characteristics by plotting the current integration, which is the integration of the current and time of the energy storage element, and the voltage corresponding to the current integration, based on the partial charge / discharge profile; The estimation device is provided with: The estimation unit estimates the overall discharge characteristics of the energy storage element based on the positive electrode single-pole characteristics, negative electrode single-pole characteristics, and the partial charge / discharge profile of the energy storage element.

2. The estimation device according to claim 1, further comprising a correction unit that corrects the positive electrode single-pole characteristics and / or the negative electrode single-pole characteristics so that the difference between the positive electrode single-pole characteristics and the negative electrode single-pole characteristics approaches the partial charge / discharge profile. The estimation device according to claim 1.

3. The estimation device according to claim 1 or 2, further comprising a completion unit that completes the overall discharge characteristics of the energy storage element obtained partially. The estimation device according to claim 1 or 2.

4. A plot generation unit that generates an electric quantity-voltage plot of the energy storage element over a required period based on the time-series data of the voltage acquired by the acquisition unit and the time-series data of the electric quantity calculated by the electric quantity calculation unit; A representative value calculation unit that calculates a representative electric quantity and a representative voltage representing the electric quantity and voltage in each divided region obtained by dividing the electric quantity-voltage plot generated by the plot generation unit by a predetermined electric quantity width; The estimation device is provided with: The generation unit: Generates a partial charge / discharge profile of the required period based on the representative electric quantity and representative voltage for each divided region calculated by the representative value calculation unit. The estimation device according to any one of claims 1 to 3.

5. The generation unit: Generates a partial charge / discharge profile of a continuous period in which the plurality of required periods are continuous, based on the partial charge / discharge profiles of each of the plurality of required periods. The estimation device according to claim 4.

6. A profile correction unit is provided to correct at least one of the first partial charge-discharge profile of one period and the second partial charge-discharge profile of the other period of a continuous required period by moving them along the charge quantity axis on the partial charge-discharge profile so that they approach each other. The generation unit generates a partial charge-discharge profile of the continuous period based on the correction by the profile correction unit. The estimation device according to claim 5.

7. Acquire time-series data of the current and voltage of the energy storage element. Calculate time-series data of the charge quantity based on the acquired time-series data of the current. Generate a partial charge-discharge profile by plotting the current integration, which is the integration of the current of the energy storage element and time, and the voltage corresponding to the current integration based on the acquired time-series data of the voltage and the calculated time-series data of the charge quantity. Estimate the overall discharge characteristics by plotting the current integration, which is the integration of the current of the energy storage element and time, and the voltage corresponding to the current integration based on the partial charge-discharge profile. Furthermore, estimate the overall discharge characteristics of the energy storage element based on the positive electrode single-pole characteristics, negative electrode single-pole characteristics, and the partial charge-discharge profile of the energy storage element. Estimation method.

8. Acquire time-series data of the current and voltage of the energy storage element. Calculate time-series data of the charge quantity based on the acquired time-series data of the current. Generate a partial charge-discharge profile by plotting the current integration, which is the integration of the current of the energy storage element and time, and the voltage corresponding to the current integration based on the acquired time-series data of the voltage and the calculated time-series data of the charge quantity. Estimate the overall discharge characteristics by plotting the current integration, which is the integration of the current of the energy storage element and time, and the voltage corresponding to the current integration based on the partial charge-discharge profile. Furthermore, estimate the overall discharge characteristics of the energy storage element based on the positive electrode single-pole characteristics, negative electrode single-pole characteristics, and the partial charge-discharge profile of the energy storage element. Diagnose the full charge capacity of the energy storage element based on the estimated overall discharge characteristics. Diagnosis method.

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